Silated core polysulfides, their preparation and use in filled elastomer compositions

ABSTRACT

This invention relates to novel sulfur-containing silane coupling agents, and organic polymers containing carbon-carbon double bonds. These novel silanes can be carried on organic and inorganic fillers. The invention also relates to articles of manufacture, particularly tires, made from the elastomer compositions described herein.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is related to the following applications, filedon even date herewith, with the disclosures of each the applicationsbeing incorporated by reference herein in their entireties:

Application Ser. No. 11/617,683, filed on Dec. 28, 2006, entitled “TireCompositions And Components Containing Silated Cyclic CorePolysulfides”.

Application Ser. No. 11/617,649, filed on Dec. 28, 2006, entitled “TireCompositions And Components Containing Free-Flowing FillerCompositions”.

Application Ser. No. 11/617,678, filed on Dec. 28, 2006, entitled “TireCompositions And Components Containing Free-Flowing FillerCompositions”.

Application Ser. No. 11/617,663, filed on Dec. 28, 2006, entitled “TireCompositions And Components Containing Silated Core Polysulfides”.

Application Ser. No. 11/617,659, filed on Dec. 28, 2006, entitled “TireCompositions and Components Containing Blocked Mercaptosilane CouplingAgent”.

Application Ser. No. 11/647,901, filed on Dec. 28, 2006, entitled“Silated Cyclic Core Polysulfides, Their Preparation And Use In FilledElastomer Compositions”.

Application Ser. No. 11/647,460, filed on Dec. 28, 2006, entitled“Silated Core Polysulfides, Their Preparation And Use In FilledElastomer Compositions”.

Application Ser. No. 11/647,903, filed on Dec. 28, 2006, entitled“Free-Flowing Filler Composition And Rubber Composition ContainingSame”.

Application Ser. No. 11/647,780, filed on Dec. 28, 2006, entitled“Blocked Mercaptosilane Coupling Agents, Process For Making And Uses InRubber”.

The present application is directed to an invention which was developedpursuant to a joint research agreement wherein the meaning of 35 U.S.C.§103(c). The joint research agreement dated May 7, 2001 as amended,between Continental AG, and General Electric Company, on behalf of GEAdvanced Materials, Silicones Division, now Momentive PerformanceMaterials Inc.

FIELD OF THE INVENTION

The present invention generally relates to silated core polysulfidescompositions, process for their preparation, and rubber compositionscomprising same.

BACKGROUND OF THE INVENTION

Sulfur-containing coupling agents used for mineral-filled elastomersinvolve silanes in which two alkoxysilylalkyl groups are bound, each toone end of a chain of sulfur atoms. The two alkoxysilyl groups arebonded to the chain of sulfur atoms by two similar, and in most cases,identical, hydrocarbon fragments. The general silane structures justdescribed, hereinafter referred to as “simple bis polysulfide silanes,”usually contain a chain of three methylene groups as the two mediatinghydrocarbon units. In some cases, the methylene chain is shorter,containing only one or two methylenes per chain. The use of thesecompounds is primarily as coupling agents for mineral-filled elastomers.These coupling agents function by chemically bonding silica or othermineral fillers to polymer when used in rubber applications. Coupling isaccomplished by chemical bond formation between the silane sulfur andthe polymer and by hydrolysis of the alkoxysilyl groups and subsequentcondensation with silica hydroxyl groups. The reaction of the silanesulfur with the polymer occurs when the S—S bonds are broken and theresulting fragment adds to the polymer. A single linkage to the polymeroccurs for each silyl group bonded to the silica. This linkage containsa single, relatively weak C—S and/or S—S bond(s) that forms the weaklink between the polymer and the silica. Under high stress, this singleC—S and/or S—S linkages may break and therefore contribute to wear ofthe filled elastomer.

The use of polysulfide silanes coupling agents in the preparation ofrubber is well known. These silanes contain two silicon atoms, each ofwhich is bound to a disubstituted hydrocarbon group, and three othergroups of which at least one is removable from silicon by hydrolysis.Two such hydrocarbon groups, each with their bound silyl group, arefurther bound to each end of a chain of at least two sulfur atoms. Thesestructures thus contain two silicon atoms and a single, continuous chainof sulfur atoms of variable length.

Hydrocarbon core polysulfide silanes that feature a central molecularcore isolated from the silicon in the molecule by sulfur-sulfur bondsare known in the art. Polysulfide silanes containing a core that is anaminoalkyl group separated from the silicon atom by a single sulfur anda polysulfide group and where the polysulfide group is bonded to thecore at a secondary carbon atom are also know in the art. As well ascore fragments in which only two polysulfide groups are attached to thecore.

When the polysulfide groups are attached directly to an aromatic core,the reactivity with the polymer (rubber) is reduced. The aromatic coreis sterically bulky which inhibits the reaction. Compositions in whichthe polysulfides are attached directly to cyclic aliphatic fragmentsderived by vinyl cyclohexene contain more than one silated core and formlarge rings. The cyclohexyl core is sterically more hindered than thearomatic core and is less reactive. Although these compositions can formmore than one sulfur linkage to the polymer rubber for each attachmentof the coupling agent to the silica through the silyl group, theireffectiveness is low due to the low reactivity.

The low reactivity is due to the attachment of the polysulfide to thesecondary carbon of cyclic core structure. The positioning of thepolysulfide group is not optimal for reaction with the accelerators andreaction with the polymer.

The present invention overcomes the deficiencies of the aforementionedcompositions involving silane coupling agents in several ways. Thesilanes of the present invention described herein are not limited to twosilyl groups nor to one chain of sulfur atoms. In fact the moleculararchitecture in which multiple polysulfide chains are oriented in anoncollinear configuration (i.e. branched, in the sense that the branchpoints occur within the carbon backbone interconnecting the polysulfidechains) is novel.

The silanes of the present invention have advantages over that in theprior art by providing a means to multiple points of sulfur attachmentto polymer per point of silicon attachment to filler. The silanesdescribed herein may be asymmetric with regard to the groups on the twoends of the sulfur chains. The silyl groups, rather than occurring atthe ends of the molecule, tend to occur more centrally and arechemically bonded to the core through carbon-carbon or carbon-siliconbonds. The core also contains multiple polysulfide groups that areattached to a primary carbon atom. The attachment decreasessignificantly the steric hinderance of the core, and increases thereactivity of the polysulfides with the polymer. This distinction iswhat allows silane silicon to become and remain bonded (through theintermediacy of a sequence of covalent chemical bonds) to polymer atmultiple points using the silanes of the present invention.

Also, without being bound by theory, silated core silanes of the presentinvention include a Y-core structure. This Y-core structure is believedto enable bonding the polymer at two different points or crosslinking ontwo different polymer chains, and also enables attachment, such as bybonding, to a filler.

The examples presented herein demonstrate that the silanes of thepresent invention impart a desirable balance of physical properties(performance to mineral-filled elastomer compositions) and better wearcharacteristics to articles manufactured from these elastomers.Improvements in rolling resistance are also apparent for elastomers usedin tire applications.

SUMMARY OF THE INVENTION

In a first embodiment of the present invention, novel silated corepolysulfides of the general Formula (1)[Y¹R¹S_(x)-]_(m)[G¹(R²SiX¹X²X³)_(a)]_(n)[G²]_(o)[R³Y²]_(p)  (1)is provided, wherein each occurrence of G¹ is independently selectedfrom a polyvalent hydrocarbon species having from 1 to about 30 carbonatoms and containing a polysulfide group represented by Formula (2)[(CH₂)_(b)—]_(c)R⁵[—(CH₂)_(d)S_(x)—]_(e);  (2)

each occurrence of G² is independently selected from a polyvalenthydrocarbon species of 1 to about 30 carbon atoms and containing apolysulfide group represented by Formula (3)[(CH₂)_(b)—]_(c)R⁵[—(CH₂)_(d)S_(x)—]_(e);  (3)

each occurrence of R¹ and R³ are independently selected from a divalenthydrocarbon fragment having from 1 to about 20 carbon atoms that includebranched and straight chain alkyl, alkenyl, alkynyl, aryl or aralkylgroups in which one hydrogen atom was substituted with a Y¹ or Y² group;

each occurrence of Y¹ and Y² is independently selected from, but notlimited to silyl (—SiX¹X²X³), carboxylic acid (—C(═O)OH), ester(—C(═O)OR⁶), in which R⁶ is any monovalent hydrocarbon group having from1 to 20 carbon atoms, and includes branched or straight chain alkyl,alkenyl, aryl or aralkyl groups), hydrogen and the like.

each occurrence of R² is a straight chain hydrocarbon represented by—(CH₂)_(f)—;

each occurrence of R⁴ is chosen independently from a polyvalenthydrocarbon fragment of 1 to about 28 carbon atom that was obtained bysubstitution of hydrogen atoms equal to the sum of a+c+e, and includecyclic, branched and straight chain alkyl, alkenyl, alkynyl, aryl andaralkyl groups in which a+c+e−1 hydrogens have been replaced, or apolyvalent heterocarbon fragment from 1 to 27 carbon atoms;

each occurrence of R⁵ is independently selected from a polyvalenthydrocarbon fragment of 1 to about 28 carbon atom that was obtained bysubstitution of hydrogen atoms equal to the sum of c+e, and includecyclic, branched and straight chain alkyl, alkenyl, alkynyl, aryl andaralkyl groups in which c+e−1 hydrogens have been replaced, or apolyvalent heterocarbon fragment from 1 to 27 carbon atoms;

each occurrence of X¹ is independently selected from hydrolyzable groupsconsisting of —Cl, —Br, —OH, —OR⁶, and R⁶C(═O)O—, wherein R⁶ is anymonovalent hydrocarbon group having from 1 to 20 carbon atoms, andincludes branched or straight chain alkyl, alkenyl, aryl or aralkylgroups;

each occurrence of X² and X³ is independently selected from the groupconsisting of hydrogen, the members listed above for R⁶, the memberslisted above for X¹ and —OSi containing groups that result from thecondensation of silanols;

each occurrence of the subscripts, a, b, c, d, e, f, m, n, o, p, and x,is independently given by a is 1 to about 3; b is 1 to about 5; c is 1to about 3; d is 1 to about 5; e is 1 to about 3; f is 0 to about 5; mis 1 to about 100, n is 1 to about 15; o is 0 to about 10; p is 1 toabout 100, and x is 1 to about 10.

In a second embodiment of the present invention, a process for thepreparation of the silated core polysulfide composition comprisingreacting a hydrocarbon or heterocarbon containing vinyl groups withHSiX¹X²X³, the resultant silylated hydrocarbon or silylated heterocarbonis reacted with a thioacid, the acyl group is removed, and the mercaptogroups are reacted with base and sulfur and followed by the reaction ofa halo containing hydrocarbon silane is disclosed.

In accordance with a third embodiment of the present invention, a rubbercomposition is provided comprising (a) a rubber component; (b) aninorganic filler; and a silated core polysulfide composition having thegeneral formula[Y¹R¹S_(x)—]_(m)[G¹(R²SiX¹X²X³)_(a)]_(n)[G²]_(o)[R³Y²]_(p)wherein Y¹, R¹S, G¹, R², X¹, X², X³, G², R³, Y², a, o, p, x, m, and nhave the aforestated meanings.

The compositions of the present invention exhibit excellent dispersionof filler and can achieve excellent workability, and improvedproductivity in vulcanization.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows HPLC analysis of the product of Example 1.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The novel silated core polysulfides of the present invention arerepresented by Formula (1)[Y¹R¹S_(x)—]_(m)[G¹(R²SiX¹X²X³)_(a)]_(n)[G²]_(o)[R³Y²]_(p)  (Formula 1)wherein each occurrence of G¹ is independently selected from apolyvalent hydrocarbon species having from 1 to about 30 carbon atomsand containing a polysulfide group represented by Formula (2)[(CH₂)_(b)—]_(c)R⁴[—(CH₂)_(d)S_(x)—]_(e);  (Formula 2)

each occurrence of G² is independently selected from a polyvalenthydrocarbon species of 1 to about 30 carbon atoms and containing apolysulfide group represented by Formula (3)[(CH₂)_(b)—]_(c)R⁵[—(CH₂)_(d)S_(x)—]_(e);  (Formula 3)

each occurrence of R¹ and R³ are independently selected from a divalenthydrocarbon fragment having from 1 to about 20 carbon atoms that includebranched and straight chain alkyl, alkenyl, alkynyl, aryl or aralkylgroups in which one hydrogen atom was substituted with a Y¹ or Y² group;

each occurrence of Y¹ and Y² is independently selected from, but notlimited to silyl (—SiX¹X²X³), carboxylic acid (—C(═O)OH), ester(—C(═O)OR⁶), wherein R⁶ is a monovalent hydrocarbon group having from 1to 20 carbon atoms, and includes branched or straight chain alkyl,alkenyl, aryl or aralkyl groups), hydrogen and the like; each occurrenceof R² is a straight chain hydrocarbon represented by —(CH₂)_(f)—; eachoccurrence of R⁴ is chosen independently from a polyvalent hydrocarbonfragment of 1 to about 28 carbon atom that was obtained by substitutionof hydrogen atoms equal to the sum of a+c+e, and include cyclic,branched and straight chain alkyl, alkenyl, alkynyl, aryl and aralkylgroups in which a+c+e−1 hydrogens have been replaced or a polyvalentheterocarbon fragment from 1 to 27 carbon atoms;

each occurrence of R⁵ is independently selected from a polyvalenthydrocarbon fragment of 1 to about 28 carbon atom that was obtained bysubstitution of hydrogen atoms equal to the sum of c+e, and includecyclic, branched and straight chain alkyl, alkenyl, alkynyl, aryl andaralkyl groups in which c+e−1 hydrogens have been replaced or apolyvalent heterocarbon fragment from 1 to 27 carbon atoms;

each occurrence of X¹ is independently selected from hydrolyzable groupsconsisting of —Cl, —Br, —OH, —OR⁶, and R⁶C(═O)O—, wherein R⁶ is anymonovalent hydrocarbon group having from 1 to 20 carbon atoms, andincludes branched or straight chain alkyl, alkenyl, aryl or aralkylgroups;

each occurrence of X² and X³ is independently selected from the groupconsisting of hydrogen, the members listed above for R⁶, the memberslisted above for X¹ and —OSi containing groups that result from thecondensation of silanols;

each occurrence of the subscripts, a, b, c, d, e, f, m, n, o, p, and x,is independently given by a is 1 to about 3; b is 1 to about 5; c is 1to about 3; d is 1 to about 5; e is 1 to about 3; f is 0 to about 5; mis 1 to about 100, n is 1 to about 15; o is 0 to about 10; p is 1 toabout 100, and x is 1 to about 10.

The term, “heterocarbon”, as used herein, refers to any hydrocarbonstructure in which the carbon-carbon bonding backbone is interrupted bybonding to atoms of nitrogen and/or oxygen, or in which thecarbon-carbon bonding backbone is interrupted by bonding to groups ofatoms containing sulfur, nitrogen and/or oxygen, such as cyanurate(C₃N₃). Heterocarbon fragments also refer to any hydrocarbon in which ahydrogen or two or more hydrogens bonded to carbon are replaced with asulfur, oxygen or nitrogen atom, such as a primary amine (—NH₂), and oxo(═O), and the like.

Thus, R⁴ and R⁵ include, but are not limited to branched,straight-chain, cyclic, and/or polycyclic polyvalent aliphatichydrocarbons, optionally containing ether functionality via oxygen atomseach of which is bound to two separate carbon atoms, polysulfidefunctionality, in which the polysulfide group (—S_(x)—) is bonded to twoseparate carbon atoms on G¹ or G² to form a ring, tertiary aminefunctionality via nitrogen atoms each of which is bound to threeseparate carbon atoms, cyano (CN) groups, and/or cyanurate (C₃N₃)groups; aromatic hydrocarbons; and arenes derived by substitution of theaforementioned aromatics with branched or straight chain alkyl, alkenyl,alkynyl, aryl and/or aralkyl groups.

As used herein, “alkyl” includes straight, branched and cyclic alkylgroups; “alkenyl” includes any straight, branched, or cyclic alkenylgroup containing one or more carbon-carbon double bonds, where the pointof substitution can be either at a carbon-carbon double bond orelsewhere in the group; and “alkynyl” includes any straight, branched,or cyclic alkynyl group containing one or more carbon-carbon triplebonds and optionally also one or more carbon-carbon double bonds aswell, where the point of substitution can be either at a carbon-carbontriple bond, a carbon-carbon double bond, or elsewhere in the group.Examples of alkyls include, but are not limited to methyl, ethyl,propyl, isobutyl. Examples of alkenyls include, but are not limited tovinyl, propenyl, allyl, methallyl, ethylidenyl norbornane, ethylidenenorbornyl, ethylidenyl norbornene, and ethylidene norbornenyl. Someexamples of alkynyls include, but are not limited to acetylenyl,propargyl, and methylacetylenyl.

As used herein, “aryl” includes any aromatic hydrocarbon from which onehydrogen atom has been removed; “aralkyl” includes any of theaforementioned alkyl groups in which one or more hydrogen atoms havebeen substituted by the same number of like and/or different aryl (asdefined herein) substituents; and “arenyl” includes any of theaforementioned aryl groups in which one or more hydrogen atoms have beensubstituted by the same number of like and/or different alkyl (asdefined herein) substituents. Some examples of aryls include, but arenot limited to phenyl and naphthalenyl. Examples of aralkyls include,but are not limited to benzyl and phenethyl, and some examples ofarenyls include, but are not limited to tolyl and xylyl.

As used herein, “cyclic alkyl”, “cyclic alkenyl”, and “cyclic alkynyl”also include bicyclic, tricyclic, and higher cyclic structures, as wellas the aforementioned cyclic structures further substituted with alkyl,alkenyl, and/or alkynyl groups. Representative examples include, but arenot limited to norbornyl, norbornenyl, ethylnorbornyl, ethylnorbornenyl,ethylcyclohexyl, ethylcyclohexenyl, cyclohexylcyclohexyl, andcyclododecatrienyl, and the like.

Representative examples of X¹ include, but are not limited to methoxy,ethoxy, propoxy, isopropoxy, butoxy, phenoxy, benzyloxy, hydroxy,chloro, and acetoxy. Representative examples of X² and X³ include therepresentative examples listed above for X¹ as well as hydrogen, methyl,ethyl, propyl, isopropyl, sec-butyl, phenyl, vinyl, cyclohexyl, andhigher straight-chain alkyl, such as butyl, hexyl, octyl, lauryl, andoctadecyl.

Representative examples of R¹ and R³ include the terminal straight-chainalkyls further substituted terminally at the other end, such as —CH₂—,—CH₂CH₂—, —CH₂CH₂CH₂—, and —CH₂CH₂CH₂CH₂CH₂CH₂CH₂CH₂—, and theirbeta-substituted analogs, such as —CH₂(CH₂)_(u)CH(CH₃)—, where u is zeroto 17; the structure derivable from methallyl chloride, —CH₂CH(CH₃)CH₂—;any of the structures derivable from divinylbenzene, such as—CH₂CH₂(C₆H₄)CH₂CH₂— and —CH₂CH₂(C₆H₄)CH(CH₃)—, where the notation C₆H₄denotes a disubstituted benzene ring; any of the structures derivablefrom diallylether, such as —CH₂CH₂CH₂OCH₂CH₂CH₂— and—CH₂CH₂CH₂OCH₂CH(CH₃)—; any of the structures derivable from butadiene,such as —CH₂CH₂CH₂CH₂—, —CH₂CH₂CH(CH₃)—, and —CH₂CH(CH₂CH₃)—; any of thestructures derivable from piperylene, such as —CH₂CH₂CH₂CH(CH₃)—,—CH₂CH₂CH(CH₂CH₃)—, and —CH₂CH(CH₂CH₂CH₃)—; any of the structuresderivable from isoprene, such as —CH₂CH(CH₃)CH₂CH₂—,—CH₂CH(CH₃)CH(CH₃)—, —CH₂C(CH₃)(CH₂CH₃)—, —CH₂CH₂CH(CH₃)CH₂—,—CH₂CH₂C(CH₃)₂— and —CH₂CH[CH(CH₃)₂]—; any of the isomers of—CH₂CH₂-norbornyl-, —CH₂CH₂-cyclohexyl-; any of the diradicalsobtainable from norbornane, cyclohexane, cyclopentane,tetrahydrodicyclopentadiene, or cyclododecene by loss of two hydrogenatoms; the structures derivable from limonene,—CH₂CH(4-methyl-1-C₆H₉—)CH₃, where the notation C₆H₉ denotes isomers ofthe trisubstituted cyclohexane ring lacking substitution in the 2position; any of the monovinyl-containing structures derivable fromtrivinylcyclohexane, such as —CH₂CH₂(vinylC₆H₉)CH₂CH₂— and—CH₂CH₂(vinylC₆H₉)CH(CH₃)—, where the notation C₆H₉ denotes any isomerof the trisubstituted cyclohexane ring; any of the monounsaturatedstructures derivable from myrcene containing a trisubstituted C═C, suchas —CH₂CH[CH₂CH₂CH═C(CH₃)₂]CH₂CH₂—, —CH₂CH[CH₂CH₂CH═C(CH₃)₂]CH(CH₃)—,—CH₂C[CH₂CH₂CH═C(CH₃)₂](CH₂CH₃)—, —CH₂CH₂CH[CH₂CH₂CH═C(CH₃)₂]CH₂—,—CH₂CH₂(C—)(CH₃)[CH₂CH₂CH═C(CH₃)₂], and—CH₂CH[CH(CH₃)[CH₂CH₂CH═C(CH₃)₂]]—; and any of the monounsaturatedstructures derivable from myrcene lacking a trisubstituted C═C, such as—CH₂CH(CH═CH₂)CH₂CH₂CH₂C(CH₃)₂—, —CH₂CH(CH═CH₂)CH₂CH₂CH[CH(CH₃)₂]—,—CH₂C(═CH—CH₃)CH₂CH₂CH₂C(CH₃)₂—, —CH₂C(═CH—CH₃)CH₂CH₂CH[CH(CH₃)₂]—,—CH₂CH₂C(═CH₂)CH₂CH₂CH₂C(CH₃)₂—, —CH₂CH₂C(═CH₂)CH₂CH₂CH[CH(CH₃)₂]—,—CH₂CH═C(CH₃)₂CH₂CH₂CH₂C(CH₃)₂—, and —CH₂CH═C(CH₃)₂CH₂CH₂CH[CH(CH₃)₂].

Representative examples of tridentate G¹ include, but are not limitedto, structures derivable from nonconjugated terminal diolefins, such as—CH₂(CH₂)_(q+1)CH(CH₂—)— and —CH(CH₃)(CH₂)_(q)CH(CH₂—)₂, in which q iszero to 20; any of the structures derivable from divinylbenzene, such as—CH₂CH₂(C₆H₄)CH(CH₂—)— and —CH₂CH₂(C₆H₃—)CH₂CH₂—, where the notationC₆H₄ denotes a disubstituted benzene ring and C₆H₃— denotes atrisubstituted ring; structures derivable from butadiene, such as—CH₂(CH—)CH₂CH₂—; any of the structures derivable from isoprene, such as—CH₂(C—)(CH₃)CH₂CH₂— and —CH₂CH(CH₃)(CH—)CH₂—; any structures derivablefrom trivinylcyclohexane, such as —CH₂(CH—)(vinylC₆H₉)CH₂CH₂—;(—CH₂CH₂)₃C₆H₉, and (—CH₂CH₂)₂C₆H₉CH(CH₃)—, where the notation C₆H₉denotes any isomer of the trisubstituted cyclohexane ring; any of thestructures derivable from myrcene, such as,—CH₂(C—)[CH₂CH₂CH═C(CH₃)₂]CH₂CH₂—, and—CH₂CH[CH₂CH₂CH═C(CH₃)₂](CH—)CH₂—; the structures derivable fromtrimethylolalkanes, such as CH₃CH₂CH₂C(CH₂—)₃ and CH₃CH₂C(CH₂—)₃;glyceryl, whose structure is —CH₂(CH—)CH₂—, and its methyl analog, whosestructure is —CH₂(—CCH₃)CH₂—; and the triethanolamine derivative,(—CH₂CH₂)₃N.

Representative examples of polyvalent G¹ include, but are not limitedto, structures derivable from nonconjugated terminal diolefins, such as—CH(CH₂—)(CH₂)_(q)CH(CH₂—)—, in which q is from 1 to 20; any of thestructures derivable from divinylbenzene, such as—CH₂(CH—)(C₆H₄)CH(CH₂—)—, where the notation C₆H₄ denotes adisubstituted benzene ring; any of the structures derivable fromdiallylether, such as —CH₂(CH—)CH₂OCH₂CH(CH₂—)—; any of the structuresderivable from butadiene, such as —CH₂(CH—)(CH—)CH₂—; any of thestructures derivable from piperylene, such as —CH₂(CH—)(CH—) CH₂(CH₃)—;any of the structures derivable from isoprene, such as—CH₂(C—)(CH₃)(CH—)CH₂—; any of the vinyl-containing structures derivablefrom trivinylcyclohexane, such as —CH₂(CH—)(vinylC₆H₉)(CH—)CH₂—,—CH₂CH₂C₆H₉—[(CH—)CH₂—]₂, —CH(CH₃)C₆H₉—[(CH—)CH₂—]₂, andC₆H₉—[(CH—)CH₂—]₃, where the notation C₆H₉ denotes any isomer of thetrisubstituted cyclohexane ring; any of the saturated structuresderivable from trivinylcyclohexane, such as —CH₂(CH—)C₆H₉—[CH₂CH₂—]₂,and —CH₂(CH—)C₆H₉—[CH(CH₃)—][CH₂CH₂—], where the notation C₆H₉ denotesany isomer of the trisubstituted cyclohexane ring; any of themonounsaturated structures derivable from myrcene containing atrisubstituted C═C, such as —CH₂(C—)[CH₂CH₂CH═C(CH₃)₂]CH₂CH₂—,—CH₂CH[CH₂CH₂CH═C(CH₃)₂](CH—)CH₂—; and pentaerythrityl, whose structureis C(CH₂—)₄.

Representative examples of didentate G² include, but are not limited to,structures derivable from nonconjugated terminal diolefins, such as—CH₂(CH₂)_(q+1)CH₂(CH₂—) and CH₂(CH₃)(CH₂)_(q)CH(CH₂—)₂, in which q iszero to 20; any of the structures derivable from divinylbenzene, such as—CH₂CH₂(C₆H₄)CH₂CH₂—, where the notation C₆H₄ denotes a disubstitutedbenzene ring; any of the structures derivable from butadiene, such as—CH₂CH₂CH₂CH₂—; any of the structures derivable from isoprene, such as—CH₂(CH)(CH₃)CH₂CH₂—, and —CH₂CH(CH₃)CH₂CH₂—; any structures derivablefrom trivinylcyclohexane, such as —CH₂CH₂(vinylC₆H₉)CH₂CH₂—, and(—CH₂CH₂)C₆H₉CH₂CH₃, where the notation C₆H₉ denotes any isomer of thetrisubstituted cyclohexane ring; any of the structures derivable frommyrcene, such as, —CH₂(CH)[CH₂CH₂CH═C(CH₃)₂]CH₂CH₂—; and thediethanolamine derivative, (—CH₂CH₂)NCH₃.

Representative examples of tridentate G² include, but are not limitedto, structures derivable from nonconjugated terminal diolefins, such as—CH₂(CH₂)_(q+1)CH(CH₂—)— in which q is zero to 20; structures derivablefrom trivinylcyclohexane, such as (—CH₂CH₂)₃C₆H₉, where the notationC₆H₉ denotes any isomer of the trisubstituted cyclohexane ring; thestructures derivable from trimethylolalkanes, such as CH₃CH₂CH₂C(CH₂—)₃and CH₃CH₂C(CH₂—)₃; and the triethanolamine derivative, (—CH₂CH₂)₃N.

Representative examples of silated core polysulfide silanes of thepresent invention include any of the isomers of2-triethoxysilyl-1,3-bis-(3-triethoxysilyl-1-propyltetrathia)propane,4-(2-triethoxysilyl-1-ethyl)-1,2-bis-(13-triethoxysilyl-3,4,5,6-tetrathiamidecyl)cyclohexane;4-(2-triethoxysilyl-1-ethyl)-1,2-bis-(13-triethoxysilyl-3,4,5,6-tetrathiamidecyl)cyclohexane;4-(2-diethoxymethylsilyl-1-ethyl)-1,2-bis-(13-triethoxysilyl-3,4,5,6-tetrathiamidecyl)cyclohexane;4-(2-triethoxysilyl-1-ethyl)-1,2-bis-(10-triethoxysilyl-3,4,5,6,7-pentathiadecyl)cyclohexane;1-(2-triethoxysilyl-1-ethyl)-2,4-bis-(10-triethoxysilyl-3,4,5,6,7-pentathiadecyl)cyclohexane;4-(2-triethoxysilyl-1-ethyl)-1,2-bis-(9-triethoxysilyl-3,4,5,6-tetrathianonyl)cyclohexane;1-(2-triethoxysilyl-1-ethyl)-2,4-bis-(9-triethoxysilyl-3,4,5,6-tetrathianonyl)cyclohexane;2-(2-triethoxysilyl-1-ethyl)-1,4-bis-(9-triethoxysilyl-3,4,5,6-tetrathianonyl)cyclohexane;4-(2-triethoxysilyl-1-ethyl)-1,2-bis-(8-triethoxysilyl-3,4,5-trithiaoctyl)cyclohexane;1-(2-triethoxysilyl-1-ethyl)-2,4-bis-(8-triethoxysilyl-3,4,5-trithiaoctyl)cyclohexane;2-(2-triethoxysilyl-1-ethyl)-1,4-bis-(8-triethoxysilyl-3,4,5-trithiaoctyl)cyclohexane;4-(2-triethoxysilyl-1-ethyl)-1,2-bis-(7-triethoxysilyl-3,4-dithiaheptyl)cyclohexane;2-(2-triethoxysilyl-1-ethyl)-1,4-bis-(7-triethoxysilyl-3,4-dithiaheptyl)cyclohexane;1-(2-triethoxysilyl-1-ethyl)-2,4-bis-(7-triethoxysilyl-3,4-dithiaheptyl)cyclohexane;2-(2-triethoxysilyl-1-ethyl)-1-(7-triethoxysilyl-3,4-dithiaheptyl)-2-(8-triethoxysilyl-3,4,5-trithiaoctyl)cyclohexane;4-(2-triethoxysilyl-1-ethyl)-1,2-bis-(9-triethoxysilyl-3,4,5,6-tetrathianonyl)benzene;bis-[2-[4-(2-triethoxysilyl-1-ethyl)-2-(9-triethoxysilyl-3,4,5,6-tetrathianonyl)cyclohexyl]ethyl]tetrasulfide;bis-[2-[4-(2-triethoxysilyl-1-ethyl)-2-(9-triethoxysilyl-3,4,5,6-tetrathianonyl)cyclohexyl]ethyl]trisulfide;bis-[2-[4-(2-triethoxysilyl-1-ethyl)-2-(9-triethoxysilyl-3,4,5,6-tetrathianonyl)cyclohexyl]ethyl]disulfide;bis-[2-[4-(2-triethoxysilyl-1-ethyl)-2-(7-triethoxysilyl-3,4-dithiaheptyl)cyclohexyl]ethyl]disulfide;bis-2-[4-(2-triethoxysilyl-1ethyl)-2-(7-triethoxysilyl-3,4-dithiaheptyl)cyclohexyl]ethyl]trisulfide;bis-[2-[4-(2-triethoxysilyl-1-ethyl)-2-(7-triethoxysilyl-3,4-dithiaheptyl)cyclohexyl]ethyltetrasulfide;bis-[2-[4-(2-triethoxysilyl-1-ethyl)-2-(9-triethoxysilyl-3,4,5,6-tetrathianonyl)phenyl]ethyl]tetrasulfide;bis-2-[4-(2-triethoxysilyl-1-ethyl)-3-bis-(9-triethoxysilyl-3,4,5,6-tetrathianonyl)cyclohexyl]ethyl]trisulfide;bis-[2-[4-(2-diiethoxymethylsilyl-1-ethyl)-2-(7-triethoxysilyl-3,4-dithiaheptyl)cyclohexyl]ethyldisulfide.

A another embodiment of the present invention the Formulae (1), (2) and(3), are described wherein each occurrence of R¹ and R³ areindependently selected from a divalent hydrocarbon fragment having from1 to about 5 carbon atoms that include branched and straight chainalkyl, alkenyl, alkynyl, aryl or aralkyl groups in which one hydrogenatom was substituted with a Y¹ or Y² group; each occurrence of Y¹ and Y²is chosen independently from silyl (—SiX¹, X², X³); each occurrence ofR² is a straight chain hydrocarbon represented by —(CH₂)_(f)— where f isan integer from about 0 to about 3; each occurrence of R⁴ is chosenindependently from a polyvalent hydrocarbon fragment of 3 to about 10carbon atom that was obtained by substitution of hydrogen atoms equal tothe sum of a+c+e, and include cyclic alkyl or aryl in which a+c+e−1hydrogens have been replaced; each occurrence of R⁵ is chosenindependently from a polyvalent hydrocarbon fragment of 3 to about 10carbon atom that was obtained by substitution of hydrogen atoms equal tothe sum of c+e, and include branched and straight chain alkyl, alkenyl,alkynyl, aryl and aralkyl groups in which c+e−1 hydrogens have beenreplaced; each occurrence of X¹ is chosen independently from the set ofhydrolyzable groups consisting of —OH, and —OR⁶, in which R⁶ is anymonovalent hydrocarbon group having from 1 to 5 carbon atoms, andincludes branched or straight chain alkyl, alkenyl, aryl or aralkylgroups; each occurrence of X² and X³ is chosen independently taken fromthe group consisting of the members listed above for R⁶, the memberslisted above for X¹ and —Si containing groups that result from thecondensation of silanols; each occurrence of the subscripts, a, b, c, d,e, f, m, n, o, p, and x, is independently given by a is 1 to about 2; bis 1 to about 3; c is 1; d is 1 to about 3; e is 1; f is 0 to about 3; mis 1, n is 1 to about 10; o is 0 to about 1; p is 1, and x is 1 to about4.

In another embodiment, 30 to 99 weight percent of the silated corepolysulfide of the present invention is blended with 70 to 1 weightpercent of another silane, including silanes of the structurerepresented in Formula (4)[X¹X²X³SiR¹S_(x)R³SiX¹X²X³]  (Formula 4)

Representative examples of the silanes described by Formula 4 are listedin U.S. Pat. No. 3,842,111, which is incorporated herein by reference,and include bis-(3-triethoxysilylpropyl)disulfide;bis-(3-triethoxysilylpropyl)trisulfide;bis-(3-triethoxysilylpropyl)tetrasulfide;bis-(3-triethoxysilylpropyl)pentasulfide;bis-(3-diethoxymethylsilylpropyl)disulfide;bis-(3-ethoxydimethylsilylpropyl)disulfide;bis-(triethoxysilylmethyl)disulfide;bis-(4-triethoxysilylbenzyl)disulfide;bis-(3-triethoxysilylphenyl)disulfide and the like.

The bonding of sulfur to a methylene group on R⁴ and R⁵ is requiredbecause the methylene group mitigates excessive steric interactionsbetween the silane and the filler and polymer. Two successive methylenegroups mitigate steric interactions even further and also addflexibility to the chemical structure of the silane, thereby enhancingits ability to accommodate the positional and orientational constraintsimposed by the morphologies of the surfaces of both the rubber andfiller at the interphase, at the molecular level. The silane flexibilitybecomes increasingly important as the total number of silicon and sulfuratoms bound to G¹ and G² increases from 3 to 4 and beyond. Structures inwhich the polysulfide group is bonded directly to secondary and tertiarycarbon atoms, ring structures, especially aromatic structures, are rigidand sterically hindered. The accelerators and curatives cannot readilyorient themselves with the polysulfide group to affect reaction and thesilated core polysulfide cannot readily orient itself to meet availablebinding sites on silica and polymer. This would tend to leave sulfurgroups unbound to polymer, thereby reducing the efficiency by which theprinciple of multiple bonding of silane to polymer via multiple sulfurgroups on silane, is realized.

The function of the other silanes in the blend is to occupy sites on thesurface of the silica which aid in dispersing the silica and couplingwith the polymer.

Process for Preparing Silated Core Polysulfides

In another embodiment of the present invention, the silated corepolysulfides are prepared by (a) reacting a hydrosilane of thestructure, HSi(X¹X²X³), with a hydrocarbon containing reactive doublebonds; (b) reacting the intermediate product from step (a) with asulfuring agent, selected from the group R⁶C(═O)SH, where R⁶ is aspreviously defined, in the presence of a free radical agent; (c)deblocking the mercapto group using a proton donator; (d) reacting theintermediate mercaptan in step c with a mixture of base and sulfur; and(e) reacting the intermediate in step d with a substituted orunsubstituted hydrocarbon containing a leaving group selected fromchlorine, bromine or iodine.

The structure of the hydrocarbon containing reactive double bonds instep (a) can be represented by the chemical structure shown if Formula(5)

wherein each occurrence is described supra and the subscripts g, h and iare independently given by g is about 0 to 3; h is 0 to about 3; and iis 0 to about 3.

The free radical reagent includes oxidizing agents that are capable ofconverting the thiocarboxylic acid to a thiocarboxylic acid radical,i.e. R⁶C(═O)S., and include, but are not limited to oxygen, peroxides,hydroperoxides, and the like.

The proton donor species are any hydrogen containing heterocarbon orsubstituted heterocarbon that is capable of reacting with thethiocarboxylic acid ester intermediate in step (c) to generate anunblocked mercaptan. Representative examples of these hydrogen donorspecies include, but are not limited to, alcohols, such as methanol,ethanol, isopropyl alcohol, propanol, and the like; amines such asammonia, methyl amine, propyl amine, diethanol amine, and the like;mercaptans, such as propyl mercaptans, butyl mercaptan, and the like.

The structure of the substituted or unsubstituted hydrocarbon containinga leaving group is represented by Formulae (6) and (7)Y¹R¹Z  (Formula 6)Y²R³Z  (Formula 7)wherein each occurrence of Y¹, Y², R¹, and R² are as previously definedand Z is selected from the group Cl, Br and I.

The reactions may be carried out in the presence or absence of organicsolvents, including alcohols, ethers, hydrocarbon solvents, and thelike. Representative examples of suitable organic solvents include, butare not limited to, ethanol, methanol, isopropyl alcohol,tetrahydrofuran, diethyl ether, hexanes, cyclohexane, toluene, xylenes,and mixtures thereof, and the like.

Use in Rubber Compositions

In one embodiment of the present invention, a rubber compositioncomprising:

(a) a rubber;

(b) the silated core polysulfide of the present invention (Formula 1);

(c) a filler.

In another embodiment of the present invention, a cured rubbercomposition comprising:

(a) a rubber;

(b) a silated core polysulfide of the present invention (Formula 1);

(c) a filler;

(d) curatives; and

(e) optionally, other additives.

The rubbers useful with the coupling agents described herein includesulfur vulcanizable rubbers including conjugated diene homopolymers andcopolymers, and copolymers of at least one conjugated diene and aromaticvinyl compound. Suitable organic polymers for preparation of rubbercompositions are well known in the art and are described in varioustextbooks including The Vanderbilt Rubber Handbook, Ohm, R. F., R.T.Vanderbilt Company, Inc., 1990 and in the Manual for the RubberIndustry, Kemperman, T and Koch, S. Jr., Bayer AG, LeverKusen, 1993.

One example of a suitable polymer for use herein is solution-preparedstyrene-butadiene rubber (SSBR). This solution prepared SSBR typicallyhas a bound styrene content in a range of 5 to 50, preferably 9 to 36,percent. Other useful polymers include emulsion-preparedstyrene-butadiene rubber (ESBR), natural rubber (NR), ethylene-propylenecopolymers and terpolymers (EP, EPDM), acrylonitrile-butadiene rubber(NBR), polybutadiene (BR), and so forth.

In another embodiment, the rubber composition is comprised of at leastone diene-based elastomer, or rubber. Suitable conjugated dienesinclude, but are not limited to, isoprene and 1,3-butadiene and suitablevinyl aromatic compounds include, but are not limited to, styrene andalpha methyl styrene. Polybutadiene may be characterized as existingprimarily, typically about 90% by weight, in the cis-1,4-butadiene form,but other compositions may also be used for the purposes describedherein.

Thus, the rubber is a sulfur curable rubber. Such diene based elastomer,or rubber, may be selected, for example, from at least one ofcis-1,4-polyisoprene rubber (natural and/or synthetic), emulsionpolymerization prepared styrene/butadiene copolymer rubber, organicsolution polymerization prepared styrene/butadiene rubber,3,4-polyisoprene rubber, isoprene/butadiene rubber,styrene/isoprene/butadiene terpolymer rubber, cis-1,4-polybutadiene,medium vinyl polybutadiene rubber (35-50 percent vinyl), high vinylpolybutadiene rubber (50-75 percent vinyl), styrene/isoprene copolymers,emulsion polymerization prepared styrene/butadiene/acrylonitrileterpolymer rubber and butadiene/acrylonitrile copolymer rubber. For someapplications, an emulsion polymerization derived styrene/butadiene(ESBR) having a relatively conventional styrene content of about 20 to28 percent bound styrene, or an ESBR having a medium to relatively highbound styrene content of about 30 to 45 percent may be used.

Emulsion polymerization prepared styrene/butadiene/acrylonitrileterpolymer rubbers containing 2 to 40 weight percent bound acrylonitrilein the terpolymer are also contemplated as diene based rubbers for usein this invention.

A particulate filler may also be added to the crosslinkable elastomercompositions of the present invention including siliceous fillers,carbon black, and so forth. The filler materials useful herein include,but are not limited to, metal oxides such as silica (pyrogenic and/orprecipitated), titanium dioxide, aluminosilicate and alumina, clays andtalc, carbon black, and so forth.

Particulate, precipitated silica is also sometimes used for suchpurpose, particularly when the silica is used in conjunction with asilane. In some cases, a combination of silica and carbon black isutilized for reinforcing fillers for various rubber products, includingtreads for tires. Alumina can be used either alone or in combinationwith silica. The term, alumina, can be described herein as aluminumoxide, or Al₂O₃. The fillers may be hydrated or in anhydrous form.

The silated core polysulfide silane(s) may be premixed or pre-reactedwith the filler particles, or added to the rubber mix during the rubberand filler processing, or mixing stages. If the silated core polysulfidesilanes and filler are added separately to the rubber mix during therubber and filler mixing, or processing stage, it is considered that thesilated core polysulfide silane(s) then combine(s) in an in-situ fashionwith the filler.

The vulcanized rubber composition should contain a sufficient amount offiller to contribute a reasonably high modulus and high resistance totear. In one embodiment of the present invention, the combined weight ofthe filler may be as low as about 5 to about 100 parts per hundred partsrubber (phr). In another embodiment, the combined weight of the filleris from about 25 to about 85 phr and at least one precipitated silica isutilized as a filler. The silica may be characterized by having a BETsurface area, as measured using nitrogen gas, in the range of about 40to about 600 m²/g. In another embodiment of the invention, the silicahas a BET surface area in a range of about 50 to about 300 m²/g. The BETmethod of measuring surface area is described in the Journal of theAmerican Chemical Society, Volume 60, page 304 (1930). The silicatypically may also be characterized by having a dibutylphthalate (DBP)absorption value in a range of about 100 to about 350, and more usuallyabout 150 to about 300. Further, the silica, as well as the aforesaidalumina and aluminosilicate, may be expected to have a CTAB surface areain a range of about 100 to about 220. The CTAB surface area is theexternal surface area as evaluated by cetyl trimethylammonium bromidewith a pH of about 9. The method is described in ASTM D 3849.

Mercury porosity surface area is the specific surface area determined bymercury porosimetry. Using this method, mercury is penetrated into thepores of the sample after a thermal treatment to remove volatiles. Setup conditions may be suitably described as using about a 100 mg sample;removing volatiles during about 2 hours at about 105° C. and ambientatmospheric pressure; ambient to about 2000 bars pressure measuringrange. Such evaluation may be performed according to the methoddescribed in Winslow, Shapiro in ASTM bulletin, p. 39 (1959) oraccording to DIN 66133. For such an evaluation, a CARLO-ERBA Porosimeter2000 might be used. The average mercury porosity specific surface areafor the silica should be in a range of about 100 to about 300 m²/g.

In one embodiment, a suitable pore size distribution for the silica,alumina and aluminosilicate according to such mercury porosityevaluation is considered herein to be such that five percent or less ofits pores have a diameter of less than about 10 nm, about 60 to about 90percent of its pores have a diameter of about 10 to about 100 nm, about10 to about 30 percent of its pores have a diameter at about 100 toabout 1,000 nm, and about 5 to about 20 percent of its pores have adiameter of greater than about 1,000 nm.

In a second embodiment the silica might be expected to have an averageultimate particle size, for example, in the range of about 10 to about50 nm as determined by the electron microscope, although the silicaparticles may be even smaller, or possibly larger, in size. Variouscommercially available silicas may be considered for use in thisinvention such as, from PPG Industries under the HI-SIL trademark withdesignations HI-SIL 210, 243, etc.; silicas available fromRhone-Poulenc, with, for example, designation of ZEOSIL 1165 MP; silicasavailable from Degussa with, for example, designations VN2 and VN3, etc.and silicas commercially available from Huber having, for example, adesignation of HUBERSIL7 8745.

In still another embodiment of the invention, the compositions mayutilize siliceous fillers such as silica, alumina and/oraluminosilicates in combination with carbon black reinforcing pigments.The compositions may comprise a filler mix of about 15 to about 95weight percent of the siliceous filler, and about 5 to about 85 weightpercent carbon black, wherein the carbon black has a CTAB value in arange of about 80 to about 150. More typically, it is desirable to use aweight ratio of siliceous fillers to carbon black of at least about 3/1in one embodiment, and at least about 10/1 in another embodiment. Thus,the weight ratio may range from about 3/1 to about 30/1 for siliceousfillers to carbon black.

In another embodiment of the invention, the filler can be comprised ofabout 60 to about 95 weight percent of said silica, alumina and/oraluminosilicate and, correspondingly, about 40 to about 5 weight percentcarbon black. The siliceous filler and carbon black may be pre-blendedor blended together in the manufacture of the vulcanized rubber.

In yet another embodiment of the present invention, the rubbercompositions of the present invention are prepared by mixing one or moreof the silated core polysulfide silanes with the organic polymer before,during or after the compounding of the filler into the organic polymer.In another embodiment, the silated core polysulfide silanes are addedbefore or during the compounding of the filler into the organic polymer,because these silanes facilitate and improve the dispersion of thefiller. In another embodiment, the total amount of silated corepolysulfide silane present in the resulting combination should be about0.05 to about 25 parts by weight per hundred parts by weight of organicpolymer (phr); and 1 to 10 phr in another embodiment. In yet anotherembodiment, fillers can be used in quantities ranging from about 5 toabout 120 phr, and still in another embodiment, fillers can be used inquantities ranging from about 25 to about 110 phr, or about 25 to about105 phr.

In practice, sulfur vulcanized rubber products typically are prepared bythermomechanically mixing rubber and various ingredients in asequentially step-wise manner followed by shaping and curing thecompounded rubber to form a vulcanized product. First, for the aforesaidmixing of the rubber and various ingredients, typically exclusive ofsulfur and sulfur vulcanization accelerators (collectively, curingagents), the rubber(s) and various rubber compounding ingredientstypically are blended in at least one, and often (in the case of silicafilled low rolling resistance tires) two or more, preparatorythermomechanical mixing stage(s) in suitable mixers. Such preparatorymixing is referred to as nonproductive mixing or non-productive mixingsteps or stages. Such preparatory mixing usually is conducted attemperatures of about 140° C. to about 200° C., and for somecompositions, about 150° C. to about 180° C. Subsequent to suchpreparatory mix stages, in a final mixing stage, sometimes referred toas a productive mix stage, curing agents, and possibly one or moreadditional ingredients, are mixed with the rubber compound orcomposition, at lower temperatures of typically about 50° C. to about130° C. in order to prevent or retard premature curing of the sulfurcurable rubber, sometimes referred to as scorching. The rubber mixture,also referred to as a rubber compound or composition, typically isallowed to cool, sometimes after or during a process intermediate millmixing, between the aforesaid various mixing steps, for example, to atemperature of about 50° C. or lower. When it is desired to mold and tocure the rubber, the rubber is placed into the appropriate mold at atemperature of at least about 130° C. and up to about 200° C. which willcause the vulcanization of the rubber by the S—S bond-containing groups(i.e., disulfide, trisulfide, tetrasulfide, etc.; polysulfide) on thesilated core polysulfide silanes and any other free sulfur sources inthe rubber mixture.

Thermomechanical mixing refers to the phenomenon whereby under the highshear conditions in a rubber mixer, the shear forces and associatedfriction occurring as a result of mixing the rubber compound, or someblend of the rubber compound itself and rubber compounding ingredientsin the high shear mixer, the temperature autogeneously increases, i.e.it “heats up”. Several chemical reactions may occur at various steps inthe mixing and curing processes.

The first reaction is a relatively fast reaction and is consideredherein to take place between the filler and the silicon alkoxide groupof the silated core polysulfides. Such reaction may occur at arelatively low temperature such as, for example, at about 120° C. Thesecond reaction is considered herein to be the reaction which takesplace between the sulfur-containing portion of the silated corepolysulfide silane, and the sulfur vulcanizable rubber at a highertemperature; for example, above about 140° C.

Another sulfur source may be used, for example, in the form of elementalsulfur, such as but not limited to S₈. A sulfur donor is consideredherein as a sulfur containing compound which liberates free, orelemental sulfur, at a temperature in a range of about 140° C. to about190° C. Such sulfur donors may be, for example, although are not limitedto, polysulfide vulcanization accelerators and organosilane polysulfideswith at least two connecting sulfur atoms in its polysulfide bridge. Theamount of free sulfur source addition to the mixture can be controlledor manipulated as a matter of choice relatively independently from theaddition of the aforesaid silated core polysulfide silane. Thus, forexample, the independent addition of a sulfur source may be manipulatedby the amount of addition thereof and by the sequence of additionrelative to the addition of other ingredients to the rubber mixture.

In one embodiment of the invention, the rubber composition may thereforecomprise about 100 parts by weight of at least one sulfur vulcanizablerubber selected from the group consisting of conjugated dienehomopolymers and copolymers, and copolymers of at least one conjugateddiene and aromatic vinyl compound, about 5 to 100 parts, preferablyabout 25 to 80 parts per hundred parts by weight per 100 parts by weightrubber of at least one particulate filler, up to about 5 parts by weightper 100 parts by weight rubber of a curing agent, and about 0.05 toabout 25 parts per hundred parts of polymer of at least one silated corepolysulfide silane as described in the present invention.

In another embodiment of the present invention, the filler comprisesfrom about 1 to about 85 weight percent carbon black based on the totalweight of the filler and 0 to about 20 parts by weight of at least onesilated core polysulfide silane based on the total weight of the filler.

In still another embodiment, the rubber composition is prepared by firstblending rubber, filler and silated core polysulfide silane, or rubber,filler pretreated with all or a portion of the silated core polysulfidesilane and any remaining silated core polysulfide silane, in a firstthermomechanical mixing step to a temperature of about 140° C. to about200° C. for about 2 to about 20 minutes. In another embodiment, fillerpretreated with all or a portion of the silated core polysulfide silaneand any remaining silated core polysulfide silane, in a firstthermomechanical mixing step to a temperature of about 140° C. to about200° C. for about 4 to 15 minutes. Optionally, the curing agent is thenadded in another thermomechanical mixing step at a temperature of about50° C. and mixed for about 1 to about 30 minutes. The temperature isthen heated again to between about 130° C. and about 200° C. and curingis accomplished in about 5 to about 60 minutes.

In another embodiment of the present invention, the process may alsocomprise the additional steps of preparing an assembly of a tire orsulfur vulcanizable rubber with a tread comprised of the rubbercomposition prepared according to this invention and vulcanizing theassembly at a temperature in a range of about 130° C. to about 200° C.

Other optional ingredients may be added in the rubber compositions ofthe present invention including curing aids, i.e. sulfur compounds,activators, retarders and accelerators, processing additives such asoils, plasticizers, tackifying resins, silicas, other fillers, pigments,fatty acids, zinc oxide, waxes, antioxidants and antiozonants, peptizingagents, reinforcing materials such as, for example, carbon black, and soforth. Such additives are selected based upon the intended use and onthe sulfur vulcanizable material selected for use, and such selection iswithin the knowledge of one of skill in the art, as are the requiredamounts of such additives known to one of skill in the art.

The vulcanization may be conducted in the presence of additional sulfurvulcanizing agents. Examples of suitable sulfur vulcanizing agentsinclude, for example elemental sulfur (free sulfur) or sulfur donatingvulcanizing agents, for example, an amino disulfide, polymericpolysulfide or sulfur olefin adducts which are conventionally added inthe final, productive, rubber composition mixing step. The sulfurvulcanizing agents, which are common in the art are used, or added inthe productive mixing stage, in an amount ranging from about 0.4 toabout 3 phr, or even, in some circumstances, up to about 8 phr, with arange of from about 1.5 to about 2.5 phr and all subranges therebetweenin one embodiment from 2 to about 2.5 phr and all subranges therebetweenin another embodiment.

Optionally, vulcanization accelerators, i.e., additional sulfur donors,may be used herein. It is appreciated that may include the followingexamples, benzothiazole, alkyl thiuram disulfide, guanidine derivativesand thiocarbamates. Representative of such accelerators can be, but notlimited to, mercapto benzothiazole (MBT), tetramethyl thiuram disulfide(TMTD), tetramethyl thiuram monosulfide (TMTM), benzothiazole disulfide(MBTS), diphenylguanidine (DPG), zinc dithiocarbamate (ZBEC),alkylphenoldisulfide, zinc iso-propyl xanthate (ZIX),N-dicyclohexyl-2-benzothiazolesulfenamide (DCBS),N-cyclohexyl-2-benzothiazolesulfenamide (CBS),N-tert-buyl-2-benzothiazolesulfenamide (TBBS),N-tert-buyl-2-benzothiazolesulfenimide (TBSI), tetrabenzylthiuramdisulfide (TBzTD), tetraethylthiuram disulfide (TETD),N-oxydiethylenebenzothiazole-2-sulfenamide, N,N-diphenylthiourea,dithiocarbamylsulfenamide, N,N-diisopropylbenzothiozole-2-sulfenamide,zinc-2-mercaptotoluimidazole, dithiobis(N-methyl piperazine),dithiobis(N-beta-hydroxy ethyl piperazine) and dithiobis(dibenzylamine). Other additional sulfur donors, may be, for example, thiuram andmorpholine derivatives. Representative of such donors are, for example,but not limited to, dimorpholine disulfide, dimorpholine tetrasulfide,tetramethyl thiuram tetrasulfide, benzothiazyl-2,N-dithiomorpholide,thioplasts, dipentamethylenethiuram hexasulfide, anddisulfidecaprolactam.

Accelerators are used to control the time and/or temperature requiredfor vulcanization and to improve the properties of the vulcanizate. Inone embodiment, a single accelerator system may be used, i.e., a primaryaccelerator. Conventionally, a primary accelerator(s) is used in totalamounts ranging from about 0.5 to about 4 phr and all subrangestherebetween in one embodiment, and from about 0.8 to about 1.5, phr andall subranges therebetween in another embodiment. Combinations of aprimary and a secondary accelerator might be used with the secondaryaccelerator being used in smaller amounts (of about 0.05 to about 3 phrand all subranges therebetween) in order to activate and to improve theproperties of the vulcanizate. Delayed action accelerators may be used.Vulcanization retarders might also be used. Suitable types ofaccelerators are amines, disulfides, guanidines, thioureas, thiazoles,thiurams, sulfenamides, dithiocarbamates and xanthates. In oneembodiment, the primary accelerator is a sulfenamide. If a secondaccelerator is used, the secondary accelerator can be a guanidine,dithiocarbamate and/or thiuram compounds. Preferably, tetrabenzylthiuramdisulfide is utilized as a secondary accelerator in combination withN-tert-buyl-2-benzothiazolesulfenamide with or withoutdiphenylguanidine. Tetrabenzylthiuram disulfide is a preferredaccelerator as it does not lead to the production of nitrosating agents,such as, for example, tetramethylthiuram disulfide.

Typical amounts of tackifier resins, if used, comprise about 0.5 toabout 10 phr and all subranges therebetween, usually about 1 to about 5phr and all subranges therebetween. Typical amounts of processing aidscomprise about 1 to about 50 phr and all subranges therebetween. Suchprocessing aids can include, for example, aromatic, napthenic, and/orparaffinic processing oils. Typical amounts of antioxidants compriseabout 1 to about 5 phr. Representative antioxidants may be, for example,diphenyl-p-phenylenediamine and others, such as, for example, thosedisclosed in the Vanderbilt Rubber Handbook (1978), pages 344-346.Typical amounts of antiozonants, comprise about 1 to about 5 phr and allsubranges therebetween. Typical amounts of fatty acids, if used, whichcan include stearic acid, comprise about 0.5 to about 3 phr and allsubranges therebetween. Typical amounts of zinc oxide comprise about 2to about 5 phr. Typical amounts of waxes comprise about 1 to about 5 phrand all subranges therebetween. Often microcrystalline waxes are used.Typical amounts of peptizers comprise about 0.1 to about 1 phr and allsubranges therebetween. Typical peptizers may be, for example,pentachlorothiophenol and dibenzamidodiphenyl disulfide.

The rubber compositions of this invention can be used for variouspurposes. For example, it can be used for various tire compounds,weather stripping, and shoe soles. In one embodiment of the presentinvention, the rubber compositions described herein are particularlyuseful in tire treads, but may also be used for all other parts of thetire as well. The tires can be built, shaped, molded and cured byvarious methods which are known and will be readily apparent to thosehaving skill in such art.

In another embodiment, the silated core polysulfide of the presentinvention compositions may be loaded on a carrier, or filler, such as,for example, a porous polymer, carbon black, silica or the like, so thatthey are in a dry free flowing form for convenient delivery to rubber.In one embodiment, the carrier would be part of the inorganic filler tobe used in the rubber.

In one embodiment of the invention, a dry free flowing compositioncomprises a silane in accordance with this invention in admixture withone or more of the aforesaid carrier materials, e.g., in a weight ratioof from about 0.1 to about 60 weight percent. The BET surface area ofsuch carriers as silica can vary widely and in one embodiment can varyfrom about 100 m²/g to about 300 m²/g. Another property of such carriersis their DOP adsorption, an oil adsorption index. In the case ofnonporous carriers such as silica, the DOP adsorption can range fromabout 100 ml/100 gm to about 400 ml/100 gm. Porous carriers such asfoamed polyolefins can advantageously absorb from about 10 ml to about250 ml/100 gm (from about 9 to about 70 weight percent) of the silane ofthe present invention.

The filler can be essentially inert to the silane with which it isadmixed as is the case with carbon black or organic polymers, or it canbe reactive therewith, e.g., the case with carriers possessing metalhydroxyl surface functionality, e.g., silicas and other siliceousparticulates which possess surface silanol functionality.

EXAMPLES

The examples presented below demonstrate significant advantages of thesilanes described herein relative those of the currently practiced art,in their performance as coupling agents in silica-filled rubber.

Example 1 Preparation of(2-triethoxysilylethyl)-bis-(7-triethoxysilyl-3,4-dithiaheptyl)cyclohexane

This example illustrates the preparation of a silated core disulide froma silane containing two vinyl groups through the formation of anintermediate thioacetate silane. The preparation of the(2-trimethoxysilylethyl)divinylcyclohexane was prepared byhydrosilation. Into a 5 L, three-neck round bottomed flask equipped withmagnetic stir bar, temperature probe/controller, heating mantle,addition funnel, condenser, and air inlet were charged1,2,4-trivinylcyclohexane (2,001.1 grams, 12.3 moles) and VCAT catalysts(1.96 grams, 0.01534 gram platinium). Air was bubbled into the vinylsilane by means of the air inlet where the tube was below the surface ofthe silane. The reaction mixture was heated to 110° C. and thetrimethoxysilane (1,204 grams, 9.9 moles) was added over a 3.5 hourperiod. The temperature of the reaction mixture increased to a maximumvalue of 130° C. The reaction mixture was cooled to room temperature and1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxylbenzyl)benzene (3grams, 0.004 mole) was added. The reaction mixture was distilled at 122°C. and 1 mmHg pressure to give 1,427 grams of(2-trimethoxysilylethyl)divinylcyclohexane, The yield was 51 percent.

The (2-triethoxysilylethyl)divinylcyclohexane was prepared bytransesterification. Into a 3 L, three-neck round bottomed flaskequipped with magnetic stir bar, temperature probe/controller, heatingmantle, addition funnel, distilling head and condenser, and nitrogeninlet were charged (2-trimethoxysilylethyl)divinylcyclohexane (284grams, 2.33 moles), sodium ethoxide in ethanol (49 grams of 21% sodiumethoxide, purchased from Aldrich Chemical) and ethanol (777 grams, 16.9moles). The reaction mixture was heated and the methanol and ethanolwere removed by distillation at atmospheric pressure. The crude productwas then distilled at 106° C. and under reduced pressure of 0.4 mmHg togive 675 grams of product, 89 percent yield.

The (2-triethoxysilylethyl)-bis-(3-thia-4-oxopentyl)cyclohexane wasprepared by addition of thioacetic acid to the divinylsilane. Into a 1L, three-neck round bottomed flask equipped with magnetic stir bar,temperature probe/controller, heating mantle, addition funnel,condenser, air inlet and a sodium hydroxide scrubber, was chargedthioacetic acid (210 grams, 2.71 moles). The(2-triethoxysilylethyl)divinylcyclohexane (400 grams, 1.23 moles) wasadded slowly over a period of 30 minutes and at room temperature bymeans of an addition funnel. The reaction was an exothermic reaction.The temperature of the mixture increased to 94.6° C. The mixture wasstirred for 2.5 hours and allowed to cool to 38.8° C. Additionalthioacetic acid (10 grams, 0.13 moles) was added and a slight exothermalreaction was observed. The reaction mixture was stirred overnight (18hours) at about 25° C. Analysis indicated that the reaction mixturecontained less than 2 percent thioacetic acid. Its overall purity was 91percent. The reaction mixture was further purified by a distillationusing a Kugel apparatus under reduced pressure.

The dimercaptosilane intermediate was prepared by removing the acetylgroups from (2-triethoxysilylethyl)-bis-(3-thia-4-oxopentyl)cyclohexane.Into a 5 L, three-neck round bottomed flask equipped with magnetic stirbar, temperature probe/controller, heating mantle, addition funnel,distilling head and condenser, 10-plate Oldershaw column and nitrogeninlet were charged(2-triethoxysilylethyl)bis-(3-thia-4-oxopentyl)cyclohexane (2,000 grams,4.1 moles), ethanol (546.8 grams, 11.8 moles) and sodium ethoxide inethanol (108 grams of a 21% sodium ethoxide in ethanol). The pH of thereaction mixture was about 8. The reaction mixture was heated to 88° C.for 24 hours to remove the ethyl acetate and ethanol from the reactionmixture. Twice ethanol (1 liter) was added to the mixture and the pH ofthe reaction mixture was increase to about 10 by the addition of 21%sodium ethoxide in ethanol (21 grams) and heated an additional 6.5hours. The reaction mixture was cooled and then pressure filtered. Thereaction mixture was stripped at a temperature less than 95° C. and 1mmHg pressure. The stripped product was filtered to give(2-triethoxysilylethyl)bis(2-mercaptoethyl)cyclohexane (1398 grams, 3.5moles, 86% yield).

The product,(2-triethoxysilylethyl)-bis-(7-triethoxysilyl-3,4-dithiaheptyl)cyclohexane,related oligomers and polysulfides, andbis-(3-triethoxysilylpropyl)polysulfide mixture, was prepared byreacting the dimercaptan silane with base, sulfur and3-chloropropyltriethoxysilane. Into a 3 liter, round bottom flaskequipped with a mechanical stirrer, temperature probe/controller,heating mantle, addition funnel, distilling head and Friedrichcondenser, and nitrogen inlet was charged(2-triethoxysilylethyl)-bis-(2-mercaptoethyl)cyclohexane (504.3 grams,1.28 moles). With rapid stirring, a solution of 21% sodium ethoxide inethanol (829 grams, 2.56 moles), an additional 150 grams of ethanol andsulfur (sublimed powder form Aldrich Chemical, 86.4 grams, 2.7 moles).The solution was refluxed 3.5 hours and then3-chloropropyltriethoxysilane (616.5 grams, 2.56 moles) over a period of1.5 hours and then refluxed 17.5 hours. The solution was cooled andpressure filtered through a 2 micron and then a 0.1 micron filter. Thefiltrate was then stripped at 60° C. and 9 mmHg to remove the ethanol.The product (1027 grams) was analyzed by HPLC and the chromatogram isshown in FIG. 1.

One isomer of(2-triethoxysilylethyl)-bis-(7-triethoxysilyl-3,4-dithiaheptyl)cyclohexanehas the following structure:

Example 2 Preparation of(2-triethoxysilylethyl)-bis-(9-triethoxysilyl-3,4,5,6-tetrathianonyl)cyclohexane

The dimercaptan silane intermediate,(2-triethoxysilylethyl)bis(2-mercaptoethyl)cyclohexane, was prepared bythe procedure described in Example 1.

The product,(2-triethoxysilylethyl)-bis-(9-triethoxysilyl-3,4,5,6-tetrathianonyl)cyclohexane,related oligomers and polysulfides, andbis-(triethoxysilylpropyl)polysulfide mixture, was prepared by reactingthe dimercaptan silane with base, sulfur and3-chloropropyltriethoxysilane. Into a 5 liter, round bottom flaskequipped with a mechanical stirrer, temperature probe/controller,heating mantle, addition funnel, distilling head and Friedrichcondenser, and nitrogen inlet was charged(2-triethoxysilylethyl)-bis-(2-mercaptoethyl)cyclohexane (596.3 grams,1.5 moles). With rapid stirring, a solution of 21% sodium ethoxide inethanol (979.0 grams, 3.0 moles), an additional 600 grams of ethanol andsulfur (sublimed powder form Aldrich Chemical, 290.0 grams, 9.1 moles).The solution was refluxed overnight and then3-chloropropyltriethoxysilane (740.0 grams, 3.07 moles) was added andrefluxed for 16 hours. The solution was cooled and pressure filteredthrough a 0.1 micron filter. The filtrate was then stripped using aRotavapor to remove the ethanol. The product (1,375 grams) was analyzedby HPLC, NMR and GC.

One isomer of(2-triethoxysilylethyl)-bis-(9-triethoxysilyl-3,4,5,6-tetrathianonyl)cyclohexanehas the following structure:

Comparative Example A-E Examples 3-7 The Use of Silanes in Low RollingResistant Tire Tread Formulation

A model low rolling resistance passenger tire tread formulation asdescribed in Table 1 and a mix procedure were used to evaluaterepresentative examples of the silanes of the present invention. Thesilane in Example 2 was mixed as follows in a “B” BANBURY® (FarrellCorp.) mixer with a 103 cu. in. (1690 cc) chamber volume. The mixing ofthe rubber was done in two steps. The mixer was turned on with the mixerat 80 rpm and the cooling water at 71° C. The rubber polymers were addedto the mixer and ram down mixed for 30 seconds. The silica and the otheringredients in Masterbatch of Table 1 except for the silane and the oilswere added to the mixer and ram down mixed for 60 seconds. The mixerspeed was reduced to 35 rpm and then the silane and oils of theMaterbatch were added to the mixer and ram down for 60 seconds. Themixer throat was dusted down and the ingredients ram down mixed untilthe temperature reached 149° C. The ingredients were then mixed for anaddition 3 minutes and 30 seconds. The mixer speed was adjusted to holdthe temperature between 152 and 157° C. The rubber was dumped (removedfrom the mixer), a sheet was formed on a roll mill set at about 85° to88° C., and then allowed to cool to ambient temperature.

In the second step, Masterbatch was recharged into the mixer. Themixer's speed was 80 rpm, the cooling water was set at 71° C. and thebatch pressure was set at 6 MPa. The Masterbatch was ram down mixed for30 seconds and then the temperature of the Masterbatch was brought up to149° C., and then the mixer's speed was reduce to 32 rpm. The rubber wasmixed for 3 minutes and 20 seconds at temperatures between 152 and 157°C. After mixing, the rubber was dumped (removed from the mixer), a sheetwas formed on a roll mill set at about 85° to 88° C., and then allowedto cool to ambient temperature.

The rubber Masterbatch and the curatives were mixed on a 15 cm×33 cm tworoll mill that was heated to between 48° and 52° C. The sulfur andaccelerators were added to the rubber (Masterbatch) and thoroughly mixedon the roll mill and allowed to form a sheet. The sheet was cooled toambient conditions for 24 hours before it was cured. The curingcondition was 160° C. for 20 minutes. Silane from Example 2 wascompounded into the tire tread formulation according to the aboveprocedure. The performance of the silane prepared in Examples 2 wascompared to the performance of silanes which are practiced in the priorart, bis-(3-triethoxysilyl-1-propyl)disulfide (TESPD), andpropyltriethoxysilane, Comparative Examples A-E. The test procedureswere described in the following ASTM methods:

Mooney Scorch ASTM D1646 Mooney Viscosity ASTM D1646 Oscillating DiscRheometer (ODR) ASTM D2084 Storage Modulus, Loss Modulus, ASTM D412 andD224 Tensile and Elongation DIN Abrasion DIN Procedure 53516 HeatBuildup ASTM D623 Percent Permanent Set ASTM D623 Shore A Hardness ASTMD2240The results of this procedure are tabulated below in Table 1.

Table 1, listed in Examples 3-7, presents the performance parameters ofhydrocarbon core polysulfide silanes of the present invention, TESPD,and propyltriethoxysilane. The physical properties of the rubbercompounded with silane from Example 2 are consistently and substantiallyhigher than the control silanes.

The silated core polysulfide silanes of the present invention impartsuperior performance to silica-filled elastomer compositions, includingbetter coupling of the silica to the rubber, as illustrated by thehigher reinforcement index. The better reinforcing index translate intoperformance improvements for the elastomer compositions and articlesmanufactured from these elastomers.

TABLE 1 Example Number Ingredients Units Comp. Ex. A Example 3 Comp. Ex.B Example 4 Comp. Ex. C Masterbatch SMR-10, natural rubber phr 10.0010.00 10.00 10.00 10.00 Budene 1207, polybutadiene phr 35.00 35.00 35.0035.00 35.00 Buna VSL 5025-1, oil-ext. sSBR phr 75.63 75.63 75.63 75.6375.63 N339, carbon black phr 12.00 12.00 12.00 12.00 12.00 Ultrasil VN3GR, silica phr 85.00 85.00 85.00 85.00 85.00 Sundex 8125TN, process oil.phr 6.37 6.37 6.37 6.37 6.37 Erucical H102, rapeseed oil phr 5.00 5.005.00 5.00 5.00 Flexzone 7P, antiozonant phr 2.00 2.00 2.00 2.00 2.00 TMQphr 2.00 2.00 2.00 2.00 2.00 Sunproof Improved, wax phr 2.50 2.50 2.502.50 2.50 Kadox 720C, zinc oxide phr 2.50 2.50 2.50 2.50 2.50 IndustreneR, stearic acid phr 1.00 1.00 1.00 1.00 1.00 Aktiplast ST, disperser phr4.00 4.00 4.00 4.00 4.00 Silane TESPD phr 6.00 6.00 6 Silane,propyltriethoxysilane phr — — — Silane Example 2 phr — 8.50 8.50Catalysts cyclohexyl amine phr 0.75 0.75 0.75 0.75 0.75 Naugex MBT phrMBTS phr TMTD phr 1.82 TMTM phr 1.58 1.58 Diphenyl guanidine phr Propylzithate phr 2.54 2.54 Rubbermakers sulfur 167 phr total phr 252.29254.78 251.32 253.82 251.56 Specific Gravity g/cm3 1.20 1.21 1.20 1.201.202 Physical Properties Mooney Viscosity at 100 Celsius mooney units71.2 72.4 77.1 72.2 ML1 + 3 Minimum Torque (Mooney Low) dNm 2.8 6.332.99 2.9 3.2 Maximum Torque (Mooney High dNm 6.45 12.41 8 14.57 12.27Torque (Max-Min) dNm 3.65 6.08 5.01 11.67 9.07 1.13 DNM RISE min 0.820.51 0.54 0.6 0.47 2.26 DNM RISE min 3.53 1.27 1.32 0.99 0.84 Cure, 160Celsius for 20 minutes T-10 min 0.39 0.39 0.36 0.67 0.44 T-40 min 1.552.07 1.33 1.92 1.36 T-95 min 24.59 26.48 23.53 22.36 18.69 cure time min20 20 20 20 20  50% Modulus MPa 0.4 0.733 0.4 0.9 0.7 100% Modulus MPa0.4 1 0.4 1.3 0.9 300% Modulus MPa 0.5 3.2 0.5 4.767 2.7 ReinforcementIndex 1.3 3.2 1.3 3.7 3 Tensile MPa 0.7 4.467 0.7 14.13 11.47 Elongation% 849.2 440.3 875.2 666.5 887.9 M300 − M100 0.1 2.2 0.1 3.5 1.8Durometer Shore “A” shore A 36.7 51.7 41.1 59.3 54.8 Zwick Rebound, RoomTemperat percent 23.8 30.9 22.3 32 28.8 Zwick Rebound, 70 Celsiuspercent 26.4 37.5 25.4 40.4 36.4 Delta Rebound, 70 C. − RT percent 2.66.6 3.1 10.4 7.6 energy at Break 4.6 10.15 4.65 41 45.69 Example NumberIngredients Units Comp. Ex. D Example 5 Comp. Ex. E Example 6 Example 7Masterbatch SMR-10, natural rubber phr 10.00 10.00 10.00 10.00 10.00Budene 1207, polybutadiene phr 35.00 35.00 35.00 35.00 35.00 Buna VSL5025-1, oil-ext. sSBR phr 75.63 75.63 75.63 75.63 75.63 N339, carbonblack phr 12.00 12.00 12.00 12.00 12.00 Ultrasil VN3 GR, silica phr85.00 85.00 85.00 85.00 85.00 Sundex 8125TN, process oil. phr 6.37 6.376.37 6.37 6.37 Erucical H102, rapeseed oil phr 5.00 5.00 5.00 5.00 5.00Flexzone 7P, antiozonant phr 2.00 2.00 2.00 2.00 2.00 TMQ phr 2.00 2.002.00 2.00 2.00 Sunproof Improved, wax phr 2.50 2.50 2.50 2.50 2.50 Kadox720C, zinc oxide phr 2.50 2.50 2.50 2.50 2.50 Industrene R, stearic acidphr 1.00 1.00 1.00 1.00 1.00 Aktiplast ST, disperser phr 4.00 4.00 4.004.00 4.00 Silane TESPD phr 6 Silane, propyltriethoxysilane phr 5.22Silane Example 2 phr 8.5 8.5 8.5 Catalysts cyclohexyl amine phr 0.750.75 0.75 0.75 0.75 Naugex MBT phr 0.1 0.1 0.1 MBTS phr 1.26 1.26 1.26TMTD phr 1.82 1.82 TMTM phr Diphenyl guanidine phr 2 2 2 Propyl zithatephr Rubbermakers sulfur 167 phr 2 2 total phr 250.78 254.06 255.10257.60 255.60 Specific Gravity g/cm3 1.199 1.204 1.207 1.208 1.204Physical Properties Mooney Viscosity at 100 Celsius mooney units 110.595.6 68.9 82.8 76.1 ML1 + 3 Minimum Torque (Mooney Low) dNm 11.7 3.622.7 3.33 2.87 Maximum Torque (Mooney High dNm 16.77 19 19.01 24.72 15.52Torque (Max-Min) dNm 5.07 15.38 16.31 21.39 12.65 1.13 DNM RISE min 0.110.44 0.52 0.38 0.57 2.26 DNM RISE min 0.15 0.61 0.68 0.51 1 Cure, 160Celsius for 20 minutes T-10 min 0.11 0.53 0.63 0.52 0.67 T-40 min 0.521.3 1.2 1.24 3.31 T-95 min 4.64 18.85 13.71 19.61 21.75 cure time min 2020 20 20 20  50% Modulus MPa 0.5 1.367 1.3 1.767 0.967 100% Modulus MPa0.5 2.4 2.3 3.367 1.367 300% Modulus MPa 0.7 11.93 10.03 14.8 5.133Reinforcement Index 1.4 5 4.4 4.4 3.8 Tensile MPa 3.3 16.73 16.17 16.0313.77 Elongation % 1280 414.9 477.7 349.6 635.6 M300 − M100 0.2 9.5 7.711.4 3.8 Durometer Shore “A” shore A 49.6 67.4 67.9 70.9 59.8 ZwickRebound, Room Temperat percent 24.2 36.4 28.9 33.8 30.4 Zwick Rebound,70 Celsius percent 27.2 49.2 45.2 52.4 41.9 Delta Rebound, 70 C. − RTpercent 3 12.8 16.3 18.6 11.5 energy at Break 21.25 31.19 36.23 27.0338.65

While the above description contains many specifics, these specificsshould not be construed as limitations of the invention, but merely asexemplifications of preferred embodiments thereof. Those skilled in theart will envision many other embodiments within the scope and spirit ofthe invention as defined by the claims appended hereto.

1. A silated core polysulfide of the general formula[Y¹R¹S_(x)—]_(m)[G¹(R²SiX¹X²X³)_(a)]_(n)[G²]_(o)[R³Y²]_(p) wherein: eachoccurrence of G¹ is independently selected from a polyvalenthydrocarbon-containing species having from 3 to about 30 carbon atomscontaining a polysulfide group represented by the general formula:[(CH₂)_(b)—]_(c)R⁴[—(CH₂)_(d)S_(x)—]_(e); each occurrence of G² isindependently selected from a polyvalent hydrocarbon-containing speciesof 3 to about 30 carbon atoms containing a polysulfide group representedby the general formula:[(CH₂)_(b)—]_(c)R⁵[—(CH₂)_(d)S_(x)—]_(e); each occurrence of R¹ and R³is independently selected from a divalent hydrocarbon fragment havingfrom 1 to about 20 carbon atoms; each occurrence of Y¹ and Y² isindependently selected from the group consisting of silyl (—SiX¹X²X³),hydrogen, carboxylic acid, ester (—C(═O)OR⁶) wherein R⁶ is a monovalenthydrocarbon group having from 1 to 20 carbon atoms; each occurrence ofR² is a chemical bond or a straight chain hydrocarbon represented by—(CH₂)_(f)—; each occurrence of X¹ is independently selected from thegroup consisting of —Cl, —Br, —OH, OR⁶, and R⁶C(═O)O—, wherein R⁶ is amonovalent hydrocarbon group having from 1 to 20 carbon atoms; eachoccurrence of X² and X³ is independently selected from the groupconsisting of hydrogen, R⁶, wherein R⁶ is a monovalent hydrocarbon grouphaving from 1 to 20 carbon atoms, X¹, wherein X¹ is independentlyselected from the group consisting of —Cl, —Br, —OH, —OR⁶, andR⁶C(═O)O—, wherein R⁶ is a monovalent hydrocarbon group having from 1 to20 carbon atoms, and —OSi containing groups that result from thecondensation of silanols; each occurrence of the subscripts, a, b, c, d,e, f, m, n, o, p, and x, is independently given wherein a, c and e are 1to about 3; b is 1 to about 5; d is 1 to about 5; f is 1 to about 5; mand p are 1 to about 100; n is 1 to about 15; o is 0 to about 10; and xis 1 to about 10; and, each occurrence of R⁴ and R⁵ is independentlyselected from a polyvalent heterocarbon fragment having from 1 to 27carbon atoms.
 2. The silated core polysulfide of claim 1 wherein theheteroatom of R⁴ and R⁵ is selected from the group consisting of sulfur,oxygen, nitrogen, and mixtures thereof.
 3. The silated core polysulfideof claim 1 wherein the value of x is from 2 to
 4. 4. A silated corepolysulfide of the general formula[Y¹R¹S_(x)—]_(m)[G¹(R²SiX¹X²X³)_(a]) _(n)[G²]_(o)[R³Y²]_(p) wherein:each occurrence of G¹ is independently selected from a polyvalenthydrocarbon-containing species having from 1 to about 30 carbon atomscontaining a polysulfide group represented by the general formula:[(CH₂)_(b)—]_(c)R⁴[—(CH₂)_(d)S_(x)—]_(e); each occurrence of G² isindependently selected from a polyvalent hydrocarbon-containing speciesof 1 to about 30 carbon atoms containing a polysulfide group representedby the general formula:[(CH₂)_(b)—]_(c)R⁵[—(CH₂)_(d)S_(x)—]_(e); each occurrence of R¹ and R³is independently selected from a divalent hydrocarbon fragment havingfrom 1 to about 20 carbon atoms; each occurrence of Y¹ and Y² isindependently selected from the group consisting of silyl (—SiX¹X²X³),hydrogen, carboxylic acid, ester (—C(═O)OR⁶) wherein R⁶ is a monovalenthydrocarbon group having from 1 to 20 carbon atoms; each occurrence ofR² is a chemical bond or a straight chain hydrocarbon represented by—(CH₂)_(f)—; each occurrence of R⁴ is independently selected from apolyvalent hydrocarbon fragment of 1 to about 28 carbon atoms saidfragment possessing a cyclic structure selected from the groupconsisting of bicyclic, tricyclic, higher cyclic structures, and cyclicstructures substituted with alkyl, alkenyl and/or alkynyl groups; eachoccurrence of R⁵ is independently selected from a polyvalent hydrocarbonfragment of 1 to about 28 carbon atoms said fragment possessing a cyclicstructure selected from the group consisting of bicyclic, tricyclic,higher cyclic structures, and cyclic structures substituted with alkyl,alkenyl and/or alkynyl groups; each occurrence of X¹ is independentlyselected from the group consisting of —Cl, —Br, —OH, —OR⁶, andR⁶C(═O)O—, wherein R⁶ is a monovalent hydrocarbon group having from 1 to20 carbon atoms and possesses a cyclic structure selected from the groupconsisting of bicyclic, tricyclic, higher cyclic structures, and cyclicstructures substituted with alkyl, alkenyl and/or alkynyl groups; eachoccurrence of X² and X³ is independently selected from the groupconsisting of hydrogen, R⁶, X¹, wherein X¹ is independently selectedfrom the group consisting of —Cl, —Br, —OH, —OR⁶, and R⁶C(═O)O—, whereinR⁶ is a monovalent hydrocarbon group having from 1 to 20 carbon atomsand possesses a cyclic structure selected from the group consisting ofbicyclic, tricyclic, higher cyclic structures, and cyclic structuressubstituted with alkyl, alkenyl and/or alkynyl groups, and —OSicontaining groups that result from the condensation of silanols; and,each occurrence of the subscripts, a, b, c, d, e, f, m, n, o, p, and x,is independently given wherein a, c and e are 1 to about 3; b is 1 toabout 5; d is 1 to about 5; f is 1 to about 5; m and p are 1 to about100; n is 1 to about 15; o is 0 to about 10; and x is 1 to about
 10. 5.The silated core polysulfide of claim 4 wherein the value of x is from 2to
 4. 6. A silated core polysulfide of the general formula[Y¹R¹S_(x)—]_(m)[G¹(R²SiX¹X²X³)_(a)]_(n)[G²]_(o)[R³Y²]_(p) wherein: eachoccurrence of G¹ is independently selected from a polyvalenthydrocarbon-containing species derived from nonconjugated diolefins, andhaving from 5 to about 30 carbon atoms containing a polysulfide grouprepresented by the general formula:[(CH₂)_(b)—]_(c)R⁴[—(CH₂)_(d)S_(x)—]_(e); each occurrence of G² isindependently selected from a polyvalent hydrocarbon-containing speciesof 3 to about 30 carbon atoms containing a polysulfide group representedby the general formula:[(CH₂)_(b)—]_(c)R⁵[—(CH₂)_(d)S_(x)—]_(e); each occurrence of R¹ and R³is independently selected from a divalent hydrocarbon fragment havingfrom 1 to about 20 carbon atoms; each occurrence of Y¹ and Y² isindependently selected from the group consisting of silyl (—SiX¹X²X³),hydrogen, carboxylic acid, ester (—C(═O)OR⁶) wherein R⁶ is a monovalenthydrocarbon group having from 1 to 20 carbon atoms; each occurrence ofR² is a chemical bond or a straight chain hydrocarbon represented by—(CH₂)_(f)—; each occurrence of R⁴ is independently selected from apolyvalent hydrocarbon fragment of 1 to about 28 carbon atoms; eachoccurrence of R⁵ is independently selected from a polyvalent hydrocarbonfragment of 1 to about 28 carbon atoms; each occurrence of X¹ isindependently selected from the group consisting of —Cl, —Br, —OH, —OR⁶,and R⁶C(═O)O—, wherein R⁶ is a monovalent hydrocarbon group having from1 to 20 carbon atoms; each occurrence of X² and X³ is independentlyselected from the group consisting of hydrogen, R⁶, wherein R⁶ is amonovalent hydrocarbon group having from 1 to 20 carbon atoms, X¹,wherein X¹ is independently selected from the group consisting of —Cl,—Br, —OH, —OR⁶, and R⁶C(═O)O—, wherein R⁶ is a monovalent hydrocarbongroup having from 1 to 20 carbon atoms, and —OSi containing groups thatresult from the condensation of silanols; and, each occurrence of thesubscripts, a, b, c, d, e, f, m, n, o, p, and x, is independently givenwherein a, c and e are 1 to about 3; b is 1 to about 5; d is about 1 to5; f is 1 to about 5; m and p are 1 to about 100; n is 1 to about 15; ois 0 to about 10; and x is 1 to about
 10. 7. The silated corepolysulfide of claim 6 wherein G¹ is selected from the group consistingof —CH₂(CH₂)_(q+1)CH(CH₂—)— and —CH(CH₃)(CH₂)_(q)CH(CH₂—)₂, wherein q iszero to
 20. 8. The silated core polysulfide of claim 6 wherein G¹ is—CH(CH₂)(CH₂)_(q)CH(CH₂—)—, in which q is from 1 to
 20. 9. The silatedcore polysulfide of claim 6 wherein the value of x is from 2 to
 4. 10. Asilated core polysulfide selected from the group consisting of2-triethoxysilyl-1,3-bis-(3-triethoxysilyl-1-propyltetrathia)propane,4-(2-triethoxysilyl-1-ethyl)-1,2-bis-(13-triethoxysilyl-3,4,5,6-tetrathiamidecyl)cyclohexane;4-(2-triethoxysilyl-1-ethyl)-1,2-bis-(13-triethoxysilyl-3,4,5,6-tetrathiamidecyl)cyclohexane;4-(2-diethoxymethylsilyl-1-ethyl)-1,2-bis-(13-triethoxysilyl-3,4,5,6-tetrathiamidecyl)cyclohexane;4-(2-triethoxysilyl-1-ethyl)-1,2-bis-(10-triethoxysilyl-3,4,5,6,7-pentathiadecyl)cyclohexane;1-(2-triethoxysilyl-1-ethyl)-2,4-bis-(10-triethoxysilyl-3,4,5,6,7-pentathiadecyl)cyclohexane;4-(2-triethoxysilyl-1-ethyl)-1,2-bis-(9-triethoxysilyl-3,4,5,6-tetrathianonyl)cyclohexane;1-(2-triethoxysilyl-1-ethyl)-2,4-bis-(9-triethoxysilyl-3,4,5,6-tetrathianonyl)cyclohexane;2-(2-triethoxysilyl-1-ethyl)-1,4-bis-(9-triethoxysilyl-3,4,5,6-tetrathianonyl)cyclohexane;4-(2-triethoxysilyl-1-ethyl)-1,2-bis-(8-triethoxysilyl-3,4,5-trithiaoctyl)cyclohexane;1-(2-triethoxysilyl-1-ethyl)-2,4-bis-(8-triethoxysilyl-3,4,5-trithiaoctyl)cyclohexane;2-(2-triethoxysilyl-1-ethyl)-1,4-bis-(8-triethoxysilyl-3,4,5-trithiaoctyl)cyclohexane;4-(2-triethoxysilyl-1-ethyl)-1,2-bis-(7-triethoxysilyl-3,4-dithiaheptyl)cyclohexane;2-(2-triethoxysilyl-1-ethyl)-1,4-bis-(7-triethoxysilyl-3,4-dithiaheptyl)cyclohexane;1-(2-triethoxysilyl-1-ethyl)-2,4-bis-(7-triethoxysilyl-3,4-dithiaheptyl)cyclohexane;2-(2-triethoxysilyl-1-ethyl)-1-(7-triethoxysilyl-3,4-dithiaheptyl)-2-(8-triethoxysilyl-3,4,5-trithiaoctyl)cyclohexane;4-(2-triethoxysilyl-1-ethyl)-1,2-bis-(9-triethoxysilyl-3,4,5,6-tetrathianonyl)benzene;bis-[2-[4-(2-triethoxysilyl-1-ethyl)-2-(9-triethoxysilyl-3,4,5,6-tetrathianonyl)cyclohexyl]ethyl]tetrasulfide;bis-[2-(4-(2-triethoxysilyl-1-ethyl)-2-(9-triethoxysilyl-3,4,5,6-tetrathianonyl)cyclohexyl]ethyl]trisulfide;bis-[2-[4-(2-triethoxysilyl-1-ethyl)-2-(9-triethoxysilyl-3,4,5,6-tetrathianonyl)cyclohexyl]ethyl]disulfide;bis-[2-[4-(2-triethoxysilyl-1-ethyl)-2-(7-triethoxysilyl-3,4-dithiaheptyl)cyclohexyl]ethyl]disulfide;bis-2-[4-(2-triethoxysilyl-1-ethyl)-2-(7-triethoxysilyl-3,4-dithiaheptyl)cyclohexyl]ethyl]trisulfide;bis-[2-[4-(2-triethoxysilyl-1-ethyl)-2-(7-triethoxysilyl-3,4-dithiaheptyl)cyclohexyl]ethyltetrasulfide;bis-[2-[4-(2-triethoxysilyl-1-ethyl)-2-(9-triethoxysilyl-3,4,5,6-tetrathianonyl)phenyl]ethyl]tetrasulfide;bis-2-[4-(2-triethoxysilyl-1-ethyl)-3-bis-(9-triethoxysilyl-3,4,5,6-tetrathianonyl)cyclohexyl]ethyl]trisulfide;bis-[2-[4-(2-diethoxymethylsilyl-1-ethyl)-2-(7-triethoxysilyl-3,4-dithiaheptyl)cyclohexyl]ethyldisulfide, and mixtures thereof.
 11. The silated core polysulfide ofclaim 10 wherein said silated core polysulfide is selected from thegroup consisting of4-(2-triethoxysilyl-1-ethyl)-1,2-bis-(9-triethoxysilyl-3,4,5,6-tetrathianonyl)cyclohexane,1-(2-triethoxysilyl-1-ethyl)-2,4-bis-(9-triethoxysilyl-3,4,5,6-tetrathianonyl)cyclohexane,2-(2-triethoxysilyl-1-ethyl)-1,4-bis-(9-triethoxysilyl-3,4,5,6-tetrathianonyl)cyclohexaneand mixtures thereof.
 12. A silated core polysulfide of the generalformula[Y¹R¹S_(x)—]_(m)[G¹(R²SiX¹X²X³)_(a)]_(n)[G²]_(o)[R³Y²]_(p) wherein: eachoccurrence of G¹ is independently selected from a polyvalenthydrocarbon-containing species having from 5 to about 30 carbon atomscontaining a polysulfide group represented by the general formula:[(CH₂)_(b)—]_(c)R⁴[—(CH₂)_(d)S_(x)—]_(e); each occurrence of G² isindependently selected from a polyvalent hydrocarbon-containing speciesof 3 to about 30 carbon atoms containing a polysulfide group representedby the general formula:[(CH₂)_(b)—]_(c)R⁵[—(CH₂)_(d)S_(x)—]_(e); each occurrence of R¹ and R³is independently selected from a divalent hydrocarbon fragment havingfrom 1 to about 5 carbon atoms; each occurrence of Y¹ and Y² isindependently selected from the group consisting of silyl (—SiX¹X²X³),hydrogen, carboxylic acid, ester (—C(═O)OR⁶) wherein R⁶ is a monovalenthydrocarbon group having from 1 to 20 carbon atoms; each occurrence ofR² is a chemical bond or a straight chain hydrocarbon represented by—(CH₂)_(f)—; each occurrence of R⁴ is independently selected from apolyvalent hydrocarbon fragment of 3 to about 10 carbon atoms; eachoccurrence of R⁵ is independently selected from a polyvalent hydrocarbonfragment of 1 to about 28 carbon atoms; each occurrence of X¹ isindependently selected from the group consisting of —Cl, —Br, —OH, —OR⁶,and R⁶C(═O)O—, wherein R⁶ is a monovalent hydrocarbon group having from1 to 20 carbon atoms; each occurrence of X² and X³ is independentlyselected from the group consisting of hydrogen, R⁶, wherein R⁶ is amonovalent hydrocarbon group having from 1 to 20 carbon atoms, X¹,wherein X¹ is independently selected from the group consisting of —Cl,—Br, —OH, —OR⁶, and R⁶C(═O)O—, wherein R⁶ is a monovalent hydrocarbongroup having from 1 to 20 carbon atoms, and —OSi containing groups thatresult from the condensation of silanols; and; each occurrence of thesubscripts, a, b, c, d, e, f, m, n, o, p, and x, is independently givenwherein a, c and e are 1 to about 3; b is 1 to about 5; d is 1 to about5; f is 1 to about 5; in and p are 1 to about 100; n is 1 to about 15; ois 0 to about 10; and x is 1 to about
 10. 13. The silated corepolysulfide of claim 12 wherein the value of x is from 2 to
 4. 14. Thesilated core polysulfide of claim 12 wherein R¹ and R³ are branchedand/or straight chain alkyl, alkenyl or alkynyl groups in which onehydrogen atom is substituted with a Y¹ or Y² group.
 15. The silated corepolysulfide of claim 12 wherein Y¹ and Y² are silyl (—SiX¹X²X³),hydrogen, carboxylic acid, or ester (—C(═O)OR⁶) wherein R⁶ is amonovalent hydrocarbon group having from 1 to 5 carbon atoms.
 16. Thesilated core polysulfide of claim 12 wherein R² is a straight chainhydrocarbon represented by —(CH₂)_(f)— where f is an integer from 1 toabout
 3. 17. The silated core polysulfide of claim 12 wherein R⁵ is apolyvalent hydrocarbon fragment of 3 to about 10 carbon atoms.
 18. Thesilated core polysulfide of claim 12 wherein X¹ is independentlyselected from the group consisting of hydrolysable —OH, and —OR⁶,wherein R⁶ is a monovalent hydrocarbon group having from 1 to 5 carbonatoms.
 19. The silated core polysulfide of claim 12 wherein X² and X³are independently selected from the group consisting of R⁶, wherein R⁶is a monovalent hydrocarbon group having from 1 to 5 carbon atoms, X¹,wherein X¹ is independently selected from the group consisting ofhydrolysable —OH, —OR⁶, and —OSi containing groups that result from thecondensation of silanols.
 20. The silated core polysulfide of claim 12wherein each occurrence of the subscripts, a, b, c, d, e, f, m, n, o, p,and x, is independently given by a is 1 to about 2; b and d are 1 toabout 3; c and e are 1; f is 1 to about 3; m and p are 1, n is 1 toabout 10; o is 0 to about 1; and x is 1 to about 4.